- ID:
- ivo://CDS.VizieR/J/AJ/143/83
- Title:
- Properties of a sample of Seyfert 1 galaxies
- Short Name:
- J/AJ/143/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a statistical study of a large, homogeneously analyzed sample of narrow-line Seyfert 1 (NLS1) galaxies, accompanied by a comparison sample of broad-line Seyfert 1 (BLS1) galaxies. Optical emission-line and continuum properties are subjected to correlation analyses, in order to identify the main drivers of the correlation space of active galactic nuclei (AGNs), and of NLS1 galaxies in particular. For the first time, we have established the density of the narrow-line region as a key parameter in Eigenvector 1 space, as important as the Eddington ratio L/L_Edd_. This is important because it links the properties of the central engine with the properties of the host galaxy, i.e., the interstellar medium (ISM). We also confirm previously found correlations involving the line width of H{beta} and the strength of the Fe II and [O III]{lambda}5007 emission lines, and we confirm the important role played by L/L_Edd_ in driving the properties of NLS1 galaxies. A spatial correlation analysis shows that large-scale environments of the BLS1 and NLS1 galaxies of our sample are similar. If mergers are rare in our sample, accretion-driven winds, on the one hand, or bar-driven inflows, on the other hand, may account for the strong dependence of Eigenvector 1 on ISM density.
Number of results to display per page
Search Results
112. QSOs in the M3 field
- ID:
- ivo://CDS.VizieR/J/A+A/392/851
- Title:
- QSOs in the M3 field
- Short Name:
- J/A+A/392/851
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a variability and proper motion (VPM) search for QSOs in the field around M3. The VPM search is demonstrated to be powerful technique for efficiently finding QSOs without major selection effects with regard to the spectral energy distribution. Remarkably, the properties of the VPM QSOs do not significantly differ from those of samples from more conventional optical search techniques. The lightcurves of the QSOs from the resulting sample provide an interesting data set for the statistical investigation of QSO long-term variability.
- ID:
- ivo://CDS.VizieR/J/AJ/123/578
- Title:
- Quasars in the Coma cluster
- Short Name:
- J/AJ/123/578
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second paper of the series about our Multiwavelength Quasar Survey. We present the observational results for the X-ray candidates in the field of the Coma Cluster. Nine new X-ray active galactic nuclei are discovered.
- ID:
- ivo://CDS.VizieR/J/A+A/416/35
- Title:
- Radio Emission from VLA FIRST Survey AGN
- Short Name:
- J/A+A/416/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the most recent (April 2003) version of the VLA FIRST survey radio catalog (Cat. <VIII/71>), we have searched for radio emission from >2800 AGN taken from the most recent (2001) version of the Veron-Cetty and Veron AGN catalog (Cat. <VII/224>, superseded by 2003, Cat. <VII/235>). These AGN lie in the ~9033 square degrees of sky already covered by the VLA FIRST survey. Our work has resulted in positive detection of radio emission from 775 AGN of which 214 are new detections at radio wavelengths.
- ID:
- ivo://CDS.VizieR/J/MNRAS/333/100
- Title:
- Radio galaxies in the 2dFGRS
- Short Name:
- J/MNRAS/333/100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use redshift determinations and spectral analysis of galaxies in the 2dF Galaxy Redshift Survey (<VII/226>) to study the properties of local radio sources with S>=1mJy. 557 objects (hereafter called the spectroscopic sample) drawn from the FIRST survey(<VIII/71>) , corresponding to 2.3 per cent of the total radio sample, are found in the 2dFGRS catalogue within the area 9h 48min<=RA<=14h 32min and -2.77{deg}<=DE<=2.25{deg} (2000), down to a magnitude limit b_J_=19.45. The excellent quality of 2dF spectra allows us to divide these sources into classes, according to their optical spectra.
- ID:
- ivo://CDS.VizieR/J/A+A/575/A55
- Title:
- Radio jet emission from GeV-emitting NLSy1
- Short Name:
- J/A+A/575/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the current study we aim at gaining understanding on the properties of radio emission and the assumed jet from four radio loud and {gamma}-ray loud Narrow Line Seyfert 1 galaxies i.e. Seyfert 1 galaxies with emission lines at the low-end of the FWHM distribution. The ultimate goal is twofold; first, the investigation whether a relativistic jet is operating at the source giving out the radio output observed and second, the quantification of the jet characteristics in order to understand possible similarities and differences with the jets found in typical blazars. The current study relies on the most systematic monitoring of radio loud and {gamma}-ray detected Narrow Line Seyfert 1 galaxies in the cm and mm radio bands conducted with the Effelsberg 100-m and IRAM 30-m telescopes. It covers the longest time baselines and the most radio frequencies, to date. This dataset of multi- wavelength, long-term radio light curves is analysed from a number of perspectives. A novel algorithm is introduced in order to extract sensible variability parameters (mainly amplitudes and timescales) which are then used for the computation of variability brightness temperatures and the corresponding Doppler factors. The jet powers are computed from the light curves to estimate the energy output and compare it with typical blazars. The dynamics of radio Spectra Energy Distributions are examined for understanding the mechanism causing the variability. The length of the available light curves for 3 of the 4 sources in the sample allowed a firm understanding of the general behaviour of the sources. They all display intensive variability which seems to be happening at a pace rather faster than what is generally seen in blazars. The flaring events become progressively more prominent as the frequency increases and show intensive spectral evolution indicative of shock evolution. The variability brightness temperatures and the associated Doppler factors are rather moderate implying a mildly relativistic jet. The computed jet powers show very energetic flows. The radio polarisation in one case, clearly implies the presence of a quiescent jet underlying recursive flaring activity. Finally, in one case, the sudden disappearance of a {gamma}-ray flare below some critical frequency in our band, urges for further investigation of the possible mechanism causing the evolution of broadband events. Despite the generally lower flux densities the sources appear to show all typical characteristics seen in blazars powered by relativistic jets. Intensive variability, spectral evolution across the different bands following evolutionary paths explained by traveling shocks, Doppler factors indicating mildly relativistic speeds.
- ID:
- ivo://CDS.VizieR/J/A+A/435/521
- Title:
- Radio Sources in Low-Luminosity AGNs. IV
- Short Name:
- J/A+A/435/521
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the completed results of a high resolution radio imaging survey of all (~200) low-luminosity active galactic nuclei (LLAGNs) and AGNs in the Palomar Spectroscopic Sample of all (~488) bright northern galaxies. The high incidences of pc-scale radio nuclei, with implied brightness temperatures >~10^7K, and sub-parsec jets argue for accreting black holes in >=50% of all LINERs and low-luminosity Seyferts; there is no evidence against all LLAGNs being mini-AGNs. The detected parsec-scale radio nuclei are preferentially found in massive ellipticals and in type 1 nuclei (i.e. nuclei with broad Halpha emission). The radio luminosity function (RLF) of Palomar Sample LLAGNs and AGNs extends three orders of magnitude below, and is continuous with, that of 'classical' AGNs. We find marginal evidence for a low-luminosity turnover in the RLF; nevertheless LLAGNs are responsible for a significant fraction of present day mass accretion.
- ID:
- ivo://CDS.VizieR/J/A+A/551/A95
- Title:
- Reduced co-added LETGS spectrum of Ark 564
- Short Name:
- J/A+A/551/A95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the 100ks X-ray spectrum of the narrow-line Seyfert 1 Galaxy Ark 564, taken with the Low Energy Transmission Grating Spectrometer (LETGS) on board Chandra. Using chisquare statistics, several continuum models of the time-averaged spectrum of this object are compared, obtaining a semi-empirical solution for the description of the intrinsic emission continuum and a physical solution for the intrinsic absorption of the system. We find that the 0.1-10keV spectrum can be well described by a power law plus two thermal components that account for the soft step. We are also able to detect and measure several narrow, unresolved absorption lines arising from highly ionized species of C, N, O, and Fe. The material seems to have a velocity consistent with the systemic velocity of the galaxy. This piece of evidence, in addition to the very low observed column density of Nh~10^20^cm^-2^, is in good agreement with the scenario of a transverse biconical outflow with a gas density of n<3x10^12^cm^-3^ at distances beyond the broad-line region r>10lt-days, but a dust torus origin cannot be ruled out.
- ID:
- ivo://CDS.VizieR/J/ApJ/755/60
- Title:
- Reverberation mapping for five Seyfert 1 galaxies
- Short Name:
- J/ApJ/755/60
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a detailed analysis of photometric and spectrophotometric data on five Seyfert 1 galaxies observed as a part of a recent reverberation mapping program. The data were collected at several observatories over a 140 day span beginning in 2010 August and ending in 2011 January. We obtained high sampling-rate light curves for Mrk 335, Mrk 1501, 3C 120, Mrk 6, and PG 2130+099, from which we have measured the time lag between variations in the 5100 {AA} continuum and the H{beta} broad emission line. We then used these measurements to calculate the mass of the supermassive black hole at the center of each of these galaxies. Our new measurements substantially improve previous measurements of M_BH_ and the size of the broad line-emitting region for four sources and add a measurement for one new object. Our new measurements are consistent with photoionization physics regulating the location of the broad line region in active galactic nuclei.
- ID:
- ivo://CDS.VizieR/J/ApJ/795/149
- Title:
- Reverberation mapping of the Seyfert 1 NGC 7469
- Short Name:
- J/ApJ/795/149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large reverberation-mapping study of the Seyfert 1 galaxy NGC 7469 has yielded emission-line lags for H{beta} {lambda}4861 and He II {lambda}4686 and a central black hole mass measurement M_BH_{approx} 1x10^7^ M_{sun}_, consistent with previous measurements. A very low level of variability during the monitoring campaign precluded meeting our original goal of recovering velocity-delay maps from the data, but with the new H{beta} measurement, NGC 7469 is no longer an outlier in the relationship between the size of the H{beta}-emitting broad-line region and the luminosity of the active galactic nucleus. It was necessary to detrend the continuum and H{beta} and He II {lambda}4686 line light curves and those from archival UV data for different time-series analysis methods to yield consistent results.
